The present invention relates generally to vehicular lamps. More specifically, the present invention relates to means used as environmental seals between lamp sockets and moveable reflectors.
All automotive forward lighting assemblies, including headlamps and fog lamps, comprise a light source which provides illumination. The light from this source is directed away from the automobile to illuminate the surface of the road and the space in front of the vehicle by a reflector. Several types of reflectors for vehicular forward lighting assemblies are used in the industry. These include parabolically-shaped reflectors which are used in standard forward lighting assemblies and elliptically-shaped reflectors which are used in projector lamps. In addition to being available in varying shapes, reflectors can also be divided into those that are moveable and those that are fixed. Moveable reflectors allow for the adjustment of the beam of the light source without the need for movement of the entire lighting assembly. To protect the light source from moisture and other harmful environmental effects, the light source is usually enclosed by the reflector and a clear or translucent cover which allows emitted light to pass through but protects the lamp bulb from the elements. However, to fully protect the light source, many lamp assemblies also include an environmental seal around the rear of the reflector known as a sealing bulb boot.
There are several qualities that are desirable in a sealing bulb boot used with a moveable reflector. First, it is desirable and necessary for the scaling bulb boot to form a tight seal around the reflector. This tight seal is required to block moisture and other elements from entering the lamp and potentially causing premature failure of the light source. Second, it is desirable for the sealing bulb boot to seal tightly around the lamp bulb socket without the need for an additional gasket around the base of the socket. The necessity of a separate gasket around the lamp bulb socket would increase the overall cost of the headlamp and therefore should be avoided. Third, it would be desirable for a sealing bulb boot to seal to a moveable reflector that has a simple mold design, preferably one which does not require additional design features over a fixed reflector. Once again this reduces the cost of the fabrication of the piece. Fourth, a successful boot design should be relatively simple to install and require a minimum number of assembly steps to secure to the reflector and around the lamp bulb socket. Any assembly steps which can be eliminated while maintaining a boot that still forms a tight seal saves money in the manufacturing and assembly process.
Current sealing bulb boot designs commonly require that the associated moveable reflector have a groove molded into it for mating with the sealing bulb boot. In particular, the sealing bulb boot is then sealed in such assemblies by being seated into the groove. In the alternative, no groove is used but the sealing bulb boot must be very tight around the “neck” of the light bulb socket to effectuate a seal. The requirement of an extra molded groove increases the price of the reflector. The alternative of a tight fit also adds cost because it makes the sealing bulb boot much more difficult to install. Current boot designs have other shortcomings as well. For example, they commonly require an extra gasket around the lamp socket base to ensure a tight seal. Also, additional means of boot retention may be required to ensure the boot does not come loose and break the environmental seal potentially causing premature light source failure.
Thus, a need exists for a sealing bulb boot which can be manufactured inexpensively, which forms a tight seal around the reflector, and which allows for the simplest assembly possible without the need for additional gaskets or sealing means. Additionally, the sealing bulb boot design should not require additional design features to be molded into the moveable reflector.